What is Antivirus Software? The 3 Types You Need to Know

By Tibor Moes / Updated: May 2023

What is Antivirus Software? The 3 Types of Antivirus You Need to Know

What is Antivirus Software?

In the digital age, understanding antivirus software is more crucial than ever. As we become increasingly reliant on technology, ensuring our devices are protected from cyber threats is paramount.

In this blog post, we’ll delve into the world of antivirus software, exploring its evolution, features, companies, and the malware types it protects you from. Let’s embark on a journey to understand what antivirus software is and how it keeps our digital lives secure.


  • Antivirus software protects your devices from malware and other cyber threats, like hackers. Through additional features, like a VPN and password manager, it can also protect your privacy and identity.
  • There are three types of antivirus based on their detection method: Signature-based, behavior-based, and machine learning. But you can also divide them according to the devices they protect.
  • To choose the right antivirus software, consider protection and performance test scores, and features like a firewall, password manager, and VPN.
  • We recommend Norton. With a 100% anti-malware score and an unlimited VPN, it’s unrivaled by any of its competitors. Read more in our review of Norton antivirus.

Don’t become a victim of cybercrime. Protect your devices with the best antivirus software and your privacy with the best VPN service.

Antivirus Software Definition and Meaning

Antivirus software is a program designed to keep computers, networks and other devices safe from malware and cyber attacks. It is capable of detecting, preventing and removing malicious software or viruses.

As cyber threats become more sophisticated, antivirus programs employ advanced techniques to combat these dangers. The primary function of antivirus software is to scan programs and files as they enter a device, comparing them to known viruses or searching for suspicious behavior.

Many antivirus software programs utilize signature-based detection, heuristic detection, and behavior-based detection to identify and combat known malware and emerging threats.

Microsoft Defender Antivirus, for instance, is a built-in antivirus solution for Windows users that offers anti-malware protection, including cloud-based protection.

With antivirus software constantly evolving and adapting to the ever-changing landscape of cyber threats, having such software installed on your device is crucial for maintaining its security and your peace of mind.

Types of antivirus software

There are many ways to divide antivirus software types. One option is to divide them according to the methods they use to identify and remove malware infections, as we’ll see below.

However, most top-rated antivirus software, like Norton and Bitdefender, use all three methods to keep your devices safe. Through the combination of these protection technologies, the most capable security solutions exist.

1. Antivirus software using signature-based detection

This method involves comparing the code of a suspicious file to a database of known malware signatures. If a match is found, the antivirus software will flag the file as a threat and take appropriate action, such as deleting or quarantining the file.

This method is fast and effective but unable to discover new malware threats. After all, it relies on a database of known malware signatures. So by design, it cannot identify malware threats that haven’t been encountered before.

2. Antivirus software using behavior-based detection

This method picks up where signature-based detection leaves off. By analyzing the behavior of a file rather than its code, it can discover new malware threats that haven’t been seen before. For example, if a program begins making numerous network connections or modifying system settings without your knowledge, it may be flagged as a threat.

This method is also called system monitoring (and sometimes heuristic detection, even though they are slightly different). Although the behavioral approach is great a spotting new malware, it is also prone to false positives, which means mistaking harmless files for malware. On top of that, it tends to be slower than signature-based detection.

3. Antivirus software using machine learning

The latest evolution in antivirus software involves machine learning. It applies algorithms and huge datasets to detect malicious patterns and identify malware. With enough computing power, it can be a very effective tool for monitoring both individual devices and large networks.

However, as algorithms are often created or improved by the Artificial Intelligence (AI), it can be a black box to humans. This means that it can be difficult for human engineers to understand how the algorithm reaches its conclusions. On top of that, when trained on an imperfect data set, the algorithm might come to the wrong conclusion on what is a safe or unsafe.

Types of antivirus software based on the operating system

Antivirus software can also be divided according to the operating system it is designed to protect. For example, there are antivirus programs for Windows, macOS, Android, and iOS. For instance, Intego is a famous antivirus program for Mac.

Choosing antivirus software compatible with your device’s operating system is essential, as using an incompatible program may cause problems or reduce the effectiveness of the antivirus software. Our preferred antivirus program, Norton, is very capable at protecting all major operating systems.

How to choose antivirus software?

There are many factors to consider when choosing antivirus software for your device. One important factor is compatibility with your operating systems. It is also essential to select a program that provides strong protection against known malware threats, and has a good track record in detecting and blocking unknown threats.

Performance impact is another important consideration. Some antivirus programs may slow down your device or consume many system resources, which can be frustrating. Therefore, choosing a program that balances solid protection and minimal impact on performance is crucial.

Another factor to consider is the prevalence of false positives, which are instances where the antivirus software incorrectly identifies a benign file as a threat. This can be frustrating and may result in losing important files or data. Therefore, choosing a program with a low rate of false positives is vital.

It is also essential to consider the reputation and privacy policy of the antivirus software company. Choose a company with a good reputation for protecting customer data and respecting privacy.

The prime example is Avast which tracked and sold the browsing habits of millions of its users. It collected this data via its Online Security browser extension and sold it via its subsidiary, Jumpshot. Although it claims to have stopped these activities and has been sold to Norton, the reputation lingers.

Cost is an important factor to consider as well. The more security features beyond anti-malware you want, the more expensive the product becomes. Only you can decide where the perfect compromise between price and protection lies. The following are the core features to consider:

Firewall: A firewall is a security system that monitors and controls the incoming and outgoing network traffic based on predetermined security rules. A firewall can be hardware-based, software-based, or a combination of both. Its primary purpose is to keep unauthorized users and malicious software out of a private network while allowing authorized users and legitimate traffic to pass through.

Password manager: A password manager is a software tool that helps users securely store and manage their login credentials for various online accounts. It generates strong, unique passwords for each account and stores them in a secure, encrypted format. This helps users avoid using weak or reused passwords, which can easily be guessed or hacked.

Virtual private network (VPN): A VPN is a network technology that creates a secure, encrypted connection over a public network (such as the internet). It allows users to transmit data as if their devices were directly connected to a private network, even if they are physically located elsewhere. VPNs are often used to protect online privacy and anonymity, as well as bypass censorship and geo-restrictions.

Parental controls: Parental controls allow parents or guardians to limit their children’s Internet usage and access to certain content. They can block inappropriate websites and apps, set time limits on device usage, and monitor online activity. Parental controls can help protect children from online dangers such as cyberbullying, predatory behavior, and exposure to inappropriate content.

Identity theft protection: Identity theft protection is a service that helps users monitor and protect their personal information from being used for fraudulent purposes. It typically includes credit monitoring, alert notifications, and recovery assistance. In addition, identity theft protection can help users detect and prevent unauthorized use of their personal information, such as credit card numbers or social security numbers.

Secure cloud storage (cloud backup): Cloud backup is a service that allows users to store copies of their data on a remote server (the “cloud“) to protect it from local disasters, hardware failures, or data loss. Cloud backup can be configured to automatically save new or changed files regularly, making it a convenient and reliable way to ensure data is always backed up and available for recovery.

Anti-phishing: Anti-phishing is a security feature that helps users identify and protect themselves against fraudulent websites or emails designed to steal sensitive information (such as login credentials or financial information). It can be implemented as a software tool that analyzes websites and emails for known phishing indicators, or as an education program that teaches users how to recognize and avoid phishing attacks.

Anti-ransomware: Anti-ransomware is a security feature that helps users protect their devices and data from ransomware attacks. Ransomware is a type of malicious code that encrypts a user’s files and demands payment (the “ransom”) in exchange for the decryption key. Anti-ransomware can detect and block ransomware attacks in real-time, or provide tools for recovering encrypted data.

Other features you could consider are:

  • Ad Blocker
  • Anti-theft
  • Dark web monitoring (identity protection)
  • Email protection
  • File encryption
  • File shredder
  • Gaming mode
  • Microphone protection
  • PC maintenance features
  • Secure browser (hardened browser to protect your online banking)
  • Spam filter
  • Startup optimizer
  • Tune up tools
  • Virtual keyboard
  • Webcam protection

Top Antivirus Companies and Their Offerings

There are several top antivirus companies offering a range of anti virus software products and services to provide antivirus protection, helping keep your devices safe from malware and other cyber threats.

In the following subsections, we’ll explore the offerings from Norton, Bitdefender, McAfee, and Kaspersky providing an quick look at the protection and features each company offers.


Norton is a popular antivirus and security software provider, offering comprehensive protection against viruses, malware, and other cyber threats for over three decades. In our tests, it proved to be the best antivirus software of 2023.

Norton’s wide selection of antivirus products and services includes malware protection, identity protection, and privacy protection, ensuring your devices and data remain secure from a variety of threats.


Bitdefender is a renowned cybersecurity software provider, offering antivirus solutions for Windows, Mac, iOS, and Android devices. With top ratings from independent testing institutions, Bitdefender provides cutting-edge security features such as machine learning and behavior protection to keep your devices safe from various threats.

Bitdefender also offers a free antivirus software for Windows users, ensuring accessible protection for all.


McAfee is an award-winning antivirus software that provides comprehensive protection against ransomware, malware, phishing, and other cyber threats. With a range of pricing options, McAfee caters to different security needs and budgets. It offers features like VPN and transaction monitoring for enhanced protection.


Kaspersky is a well-known antivirus software with over 20 years of experience in the industry, providing protection against viruses, malware, and ransomware.

Offering both free and paid antivirus solutions, Kaspersky ensures accessible protection for all users, with high detection rates and a variety of features such as real-time protection, scheduled scans, and extra security measures to complement antivirus software.

Free vs. Paid Antivirus Solutions

Free antivirus software is widely available and can provide basic protection against malware threats. However, these free solutions often lack features such as firewalls, VPNs, password managers, identity theft protection, mobile security, and support services, which are typically included in paid antivirus software.

Paid antivirus software offers more comprehensive protection and additional features, ensuring your devices and data are better protected from various cyber threats. While free solutions may suffice for users with limited security needs, investing in a paid antivirus software provides a higher level of protection and peace of mind.

Types of Malware Targeted by Antivirus Software

Antivirus software targets a wide array of malware types, each posing unique challenges and risks. In the following subsections, we’ll explore various examples of malware, such as adware, botnets, keyloggers, phishing, ransomware, rootkits, spyware, trojans, viruses, and worms. And how antivirus software protects against each.


Adware is unwanted software that displays ads on your computer or mobile device, generating revenue for its creators. Often installed without the user’s knowledge alongside other applications, adware can bog down your device’s performance, inundate you with pop-ups, and even compromise your personal information.

To avoid adware, exercise caution when downloading applications, read terms and conditions carefully, and use a reliable antivirus software to safeguard your device.


Botnets are networks of computers infected with malware and controlled by a single individual, known as the “bot-herder.” These networks are typically used for malicious activities such as distributed denial-of-service (DDoS) attacks or stealing personal information.

To protect your systems from botnets, employ strong passwords, keep your system up-to-date, and use antivirus software.


Keyloggers are software or hardware that record every keystroke made on a computer or mobile device, potentially stealing passwords and personal information. These programs can be used for both legitimate and malicious purposes.

Keyloggers capture keystrokes and store them in a log file, which can then be accessed by the person who installed the keylogger. To protect against keyloggers, use a trusted antivirus software with rootkit detection and heuristic-based detection, ensuring maximum protection.


Phishing is a cyber attack where an attacker poses as a trustworthy entity or person to deceive victims into revealing sensitive information or downloading malware. This can be done through deceptive emails, websites, or other forms of communication. Common types of phishing attacks include spear phishing, whaling, and smishing, all designed to target specific individuals or organizations.

To stay safe from phishing attacks, avoid clicking on links or opening attachments from unknown sources, use strong passwords, and keep your antivirus software updated.


Ransomware is a type of malware that encrypts files on a victim’s device and demands payment for their release. It poses significant risks to individuals and businesses, often leading to data loss, financial loss, and the potential for further attacks.

To protect against ransomware, keep your devices up-to-date with the latest security patches, use strong passwords, and employ a reliable antivirus program.


Rootkits are a form of malware that gain full administrative access to a computer while remaining undetectable to users and antivirus programs. Rootkits can cause significant damage to the operating system and even disable antivirus programs, leaving the device unprotected.

Although removing rootkits can be challenging, antivirus programs with rootkit detection capabilities can help identify and remove these threats.


Spyware is a type of malware that secretly installs on a device without the user’s knowledge and collects data from the device and user, sending it to third parties without permission. Spyware can monitor user activity, create targeted ads, and compromise personal information.

To protect against spyware, ensure your operating system and antivirus software are up-to-date, use strong passwords, and remain vigilant when encountering suspicious emails or websites.


Trojans are malicious software disguised as useful applications, capable of corrupting files, stealing data, and creating backdoor access points to a computer. Often spread through malicious links, downloads, or email attachments containing malicious code, trojans pose a significant threat to devices and data.

To protect against trojans, use a trusted antivirus program and exercise caution when clicking on links or downloading files from unknown sources.


Viruses are a type of malicious software that can replicate themselves and spread to other programs or computers, causing damage to the system. Typically spread through email attachments, downloads, or removable media, viruses can corrupt or erase files, steal personal information, and slow down a computer’s performance.

To protect against viruses, use antivirus software to detect viruses, keep your computer updated with the latest security patches, and be cautious when downloading files and opening email attachments.


Worms are a type of malicious software that can spread to other computers without human intervention, exploiting security vulnerabilities in computer systems and networks. To stay safe from worms, use a reliable antivirus program with on-access scanning enabled.

As with viruses, use antivirus software to detect worms, keep your PC updated with the latest patches, and be careful when downloading files and opening email attachments.

Real-Time Protection and Scheduled Scans

Real-time protection is the automatic protection provided by most antivirus, anti-spyware, and anti-malware programs. It monitors your computer system for suspicious activity, such as viruses, spyware, adware, and other malicious objects, providing continuous security.

Scheduled scans, on the other hand, are periodic checks of the system to ensure there are no malicious objects present. These scans can be set to run at regular intervals, providing an additional layer of protection alongside real-time protection. Together, real-time protection and scheduled scans ensure comprehensive protection for your devices and data.

Additional Security Measures

In addition to antivirus software, there are several other security measures you can implement to enhance your device’s protection. Firewalls, for example, are network security systems that monitor and control incoming and outgoing network traffic based on predetermined security rules, providing an additional layer of protection against cyber threats.

Virtual Private Networks (VPNs) create secure connections between devices over the internet, encrypting data and helping to protect users from malicious activities.

Password managers store and manage your passwords, helping you create strong, unique passwords for each account and keeping them safe.

Implementing these additional security measures in conjunction with antivirus software can provide a more robust defense against cyber threats.

Keeping Your Antivirus Software Up-to-Date

Ensuring your antivirus software is up-to-date is essential for maintaining maximum protection against cyber threats. As new malware and viruses emerge, antivirus companies continuously update their software to combat these evolving dangers. By keeping your antivirus software current, you can be confident that your devices are protected against the latest threats.

Sometimes, it helps to switch off your antivirus software when you are setting up updates like Windows Service Packs or revising the graphics card drivers. This action ensures that the installation process runs smoothly. However, it’s crucial to re-enable your antivirus software as soon as possible to maintain ongoing protection against potential threats.

Common Misconceptions About Antivirus Software

A common misconception about antivirus software is that it provides foolproof protection against all cyber threats. While antivirus software is designed to detect and remove a wide range of malicious software, it is not a guaranteed solution to all security issues.

Maintaining a multi-layered security approach, including firewalls, VPNs, and password managers, can help to ensure comprehensive protection for your devices and data. This is the core reason why paid antivirus software offers better protection than free antivirus programs.

Another misconception is that antivirus software slows down computers. While some antivirus programs may consume system resources, most modern antivirus software are designed to operate efficiently, minimizing any impact on device performance.

By keeping your antivirus software up-to-date and complementing it with additional security measures, you can maintain optimal device performance while safeguarding against various cyber threats.


In conclusion, antivirus software is an essential component of any device’s security, providing protection against a wide range of malware threats. As cyber threats continue to evolve, antivirus programs must adapt to offer comprehensive protection in an ever-changing landscape.

By understanding the various types of malware, selecting the right antivirus software from top companies, and implementing additional security measures, you can ensure the security of your devices and data in 2023 and beyond.

How to stay safe online:

  • Practice Strong Password Hygiene: Use a unique and complex password for each account. A password manager can help generate and store them. In addition, enable two-factor authentication (2FA) whenever available.
  • Invest in Your Safety: Buying the best antivirus for Windows 11 is key for your online security. A high-quality antivirus like Norton, McAfee, or Bitdefender will safeguard your PC from various online threats, including malware, ransomware, and spyware.
  • Be Wary of Phishing Attempts: Be cautious when receiving suspicious communications that ask for personal information. Legitimate businesses will never ask for sensitive details via email or text. Before clicking on any links, ensure the sender's authenticity.
  • Stay Informed. We cover a wide range of cybersecurity topics on our blog. And there are several credible sources offering threat reports and recommendations, such as NIST, CISA, FBI, ENISA, Symantec, Verizon, Cisco, Crowdstrike, and many more.

Happy surfing!

Frequently Asked Questions

Below are the most frequently asked questions.

Why do you need antivirus software?

Antivirus software is essential for protecting your device from malware threats and ensuring the security of your personal and sensitive information. Without antivirus software, your device is vulnerable to attacks from a range of malware, including viruses, worms, and ransomware.

What antivirus software are best?

We have tested a wide range of antivirus software over the years. We can confidently say that Norton and Bitdefender are currently the best antivirus programs for Windows. Especially Norton, which is the only brand with a 100% anti-malware test score and includes an unlimited VPN for free, is excellent.

Free vs. paid antivirus software?

We don’t advise using free antivirus software. They rarely offer better protection than the built-in tools in Windows (Microsoft Defender or Windows Defender) and macOS (XProtect and GateKeeper). And worse, they are often loaded with ads or bloatware (unwanted and annoying software that will automatically install on your PC). Avoid problems and buy paid antivirus software instead.

How does antivirus software work?

Antivirus software works by scanning the files on your computer for known malware patterns and quarantining or deleting any infected files it finds. It also checks the websites you visit and emails you receive for potential threats and alerts you if it finds any.

Author: Tibor Moes

Author: Tibor Moes

Founder & Chief Editor at SoftwareLab

Tibor has tested 39 antivirus programs and 30 VPN services, and holds a Cybersecurity Graduate Certificate from Stanford University.

He uses Norton to protect his devices, CyberGhost for his privacy, and Dashlane for his passwords.

You can find him on LinkedIn or contact him here.